The reason that your floor drain backs up or has standing water in it is because it is the lowest opening in the house for the waste piping system. Water coming up out of the floor drain is the result when one of the pipes under the basement floor and beyond are obstructed.  The waste piping will not drain due to accumulation in the pipes of greasy wastes from the kitchen sink, lint from the dryer, or tree roots. Tree roots obstructing the waste piping can occur well inside the home under the basement floor. The next part of this discussion will help you evaluate which waste pipe is most likely clogged.

A warning sign that the downstream pipe is partially clogged is if you find ONLY wetness around the floor drain (e.g. after running a load of laundry in the machine or a toilet is flushed). This is because the water backs up out of the drain only when the machine is emptying or a toilet is flushed and then the water goes away soon after.

Basement drain piping in a home - a simplified version

Basement drain piping in a home a simplified version


In most Minneapolis homes the kitchen is directly above the basement laundry area. The picture shows a simplified version of your home. In most homes there are two (not just one as shown in the picture) 1-1/2 inch or 2 inch pipes bringing waste water down into the same drain pipe to which the floor drain is connected. One of these is the drain for the kitchen sink and one is for the laundry tub. All of these pipes (2 sinks and floor drain) come together in a 2 inch pipe and go towards the “stack”, which is the four inch vertical pipe bringing waste water down from the bathrooms above. When one of the sinks (kitchen or laundry) is used and the 2 inch pipe downstream is clogged, water comes up out of the floor drain. The water will be soapy or clear-ish. This is the easiest clog to be able to delay having the line (2 inch) cleared. Just run water slowly in one of the sinks and see how fast water backs up out of the floor drain. Call me and I can take care of this for you.

If the main sewer out to the street is clogged, water will back up out of the floor drain In this case there will be a distinctly foul smell, blackish water or tissue paper in the water or on the floor around the drain. On occasion, this same symptom will occur in a basement bathroom shower.

If there is no standing water at the floor drain, you may be able to survive until the next business day.  This is because water in the main sewer (pipe to the street) is slowly draining past the blockage leaving an empty pipe. You might try running small amounts of water and see how quickly water comes out of the floor drain. Or you might be able to get by only flushing the toilet only when there is solid waste. The best approach obviously is to not use any plumbing before having a sewer service clear the line to the street. This requires a large, expensive machine that I do not have. If you need a recommendation of a company to call I can refer you to another owner/operator who only does drain service. If it is the middle of the night, Sunday or holiday you’ll have to try one of the big guys.

It is no surprise to me when people report a drain emergency over the holidays. If you are a previous customer (or are very logical and can take clues from this post) I can send you instructions of how to test your drain system. Using my methods you can determine in ADVANCE if you have a back-up waiting to happen. By testing your drain pipes you can avoid an expensive, inconvenient mess and disruption to your holiday!